STAX SR-X9000 Flagship Electrostatic Earspeakers

£5,195.00 inc. VAT

Trade-in available.

Twenty years of headphone evolution have passed since the STAX SR-Ω was released. Through constant development of electrostatic driver technology, plus the creation of the SR-009, STAX Audio have now realized the next stage of earspeaker evolution with the 2021 flagship SR-X9000 model.

Available in Aluminium / Black / Brown finish only.


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SR-X9000 is the new flagship electrostatic earspeaker from STAX Audio.

The STAX SR-X9000 features the new MLER-3 four-layer fixed electrode combined with a big metal mesh, reducing air resistance and the effect of reflection, and thus delivering far higher sonic transparency. Metal mesh is the ideal material of fixed electrodes, but can be very difficult to manufacture. STAX have applied their diffused junction (thermocompression bonding) technology, acquired when manufacturing the SR-009 and SR-009S, which has produced excellent results.

The diaphragm is made of ultra-thin super-engineering plastic film. Due to improved weight-saving (close to zero grams), far greater transient characteristics are realised. From the bass to the high-end, the linearity of the sound is improved. The area of the diaphragm has increased by 20% compared to SR-009S, delivering the widest soundfield ever in a STAX earspeaker.

The enclosure of the sound unit is made of tough machined aluminium. This new design firmly fixes the sound unit and completely eliminates unnecessary vibrations. The sound wave from the unit flows more smoothly. The improved acoustic characteristic inside the enclosure delivers clearer sound unaffected by sound reflection.

Guard mesh installed parallel to a sound element generates direct reflections which can badly affect the sound. This problem is solved for SR-X9000 – the guard mesh pillars are of different lengths in front and back, changing the height of the gap between the sound element and the guard mesh. So the guard mesh is not parallel to the sound element, and the reflection angle is completely controlled. The sound wave flows smoothly.

The main material of the arc assembly has been upgraded to stainless steel, making it more tolerant to torsion and a more stable fit onto the ears. The material of the headband pad which directly contacts to the skin is genuine leather. The position can be adjusted by the slider parts with 9-step click adjustment system.

The material of the ear pads is genuine sheepskin leather which has excellent breathability and softness. Genuine leather makes the earspeaker a close, comfortable fit for extended periods, allowing you to fully enjoy the high-quality bass and vivid sound without getting fatigued.

The material of the core cable is a 6NCu ultra-pure annealed copper wire, which is wrapped in silver plated annealed copper wire. This means both high and low frequencies are improved. The cable is detachable and can be replaced, whilst two cables (2.5 m and 1.5 m lengths) are supplied, allowing you to choose which cable best suits your listening style.

The storage case is made of Paulownia Wood, which has low thermal conductivity and humidity control capacity – the best storage solution available.


  • New flagship STAX earspeaker, 20 years of evolution since SR-Omega.
  • Improved MLER-3 four-layer metal mesh fixed electrode.
  • Diffused junction bonding.
  • 20% increase in diaphragm size.
  • Widest soundfield ever realised.
  • Machined aluminium enclosure.
  • Tilt mesh-guard design.
  • Stainless steel arc with fully adjustable click system.
  • Genuine leather earpads.
  • Ultra-pure low-capacity wide hybrid 6NBu cables.


  • Type: Push-pull electrostatic large circular sound element, open-air type enclosure.
  • Electrode: MLER-3
  • Frequency Response: 5 – 42,000 Hz
  • Electrostatic capacitance: 110 pF (including cable)
  • Impedance: 145 kΩ (including cable, at 10 kHz)
  • Sound Pressure Sensitivity: 100 dB / input 100 V r.m.s. / 1 kHz
  • Bias Voltage: DC 580 V
  • Right / Left Channel Indication: Golden solid line (left) and dotted line (right) on the cable
  • Earpad: Genuine leather (skin touching portion), high-quality artificial leather (surrounding portion)
  • Cable: Silver-coated 6N (99.9999%) OFC parallel 6-strand, low-capacity special wide cables (2.5 m, 1.5 m)
  • Weight: 432 g (without cable)


  • SR-X9000 Electrostatic Earspeakers.
  • Low-Capacity Wide Hybrid 6NCu Cables (2.5 m / 1.5 m).
  • Paulownia Wood Storage Case.

Full STAX Range Available

Unilet Sound & Vision are long-term official retail partners for STAX Audio, providing sales, advice and assistance on their entire range of high-quality products. Please do get in touch if you would like a demonstration or wish to purchase.

More Information

Additional information

Weight 0.650 kg
Purchase Options

Click & Collect, Trade-In Available


Silver / Brown / Black



Founded in 1938, STAX brought the world's first electrostatic headphone to market in 1960. Today they continue their long tradition by offering the finest audio products for both professional and audiophile applications.

All STAX headphones are referred to as "earspeakers" - the company states that such ultra-high fidelity devices can only be compared with the best cost-no-object loudspeakers, not other headphones. Their unique amplifiers, earspeakers and drivers are highly sought-after products, and extremely well considered by aficionados in the audio industry.

Unilet Sound & Vision are one of the oldest STAX dealers in the UK, and one of the very few official outlets stocking their products. Do get in touch with us if you would like to audition the range, or need advice or assistance with choosing the right system for your needs.

STAX | Unilet Sound & Vision


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